The present invention relates to a method for preparing frozen baker's dough and more specifically to a method for preparing frozen baker's dough which permits the production of bread exhibiting excellent properties comparable to those observed for the bread prepared by the usual integrated work.
Various kinds of bread have been known and all kinds of bread must be produced every day in order to supply fresh products to the consuming public. Accordingly, it is inevitable to produce various kinds of bread in small amounts. However, if bread having various properties comparable to those observed for the bread produced by the usual integrated work can be obtained using frozen baker's dough which has been prepared in advance and frozen and stored in the frozen state, it will be possible to mass-produce baker's dough, store it in the frozen state, thaw a necessary quantity thereof at a desired time and continue the subsequent processes required for the production of bread to produce a desired quantity of bread. In other words, fresh bread can always be supplied to the consuming public while making the production schedule in bread-baking factory smooth.
However, the use of such frozen baker's dough suffers from various problems. For instance, 1 a quite long proof time is required, 2 the volume of the resulting bread is reduced, 3 the walls of foams present in the crumb of the bread become thicker and thus the bread has bad taste and texture, 4 the crust of the bread has a rough surface and 5 the bread has a distorted shape, as compared with the bread prepared by the usual integrated work.
It has been believed that the foregoing drawbacks are caused by the deterioration of yeast due to freezing; the effect of reducing substances released from the deteriorated yeast; and the destruction of the structure of the dough by the degeneration of gluten through freezing and the breakage of the gluten membrane due to the formation of ice or crystallization of water [Yasuo TANAKA, Toshiaki NAKAE, "REITO KIJI NO RIRON TO JISSAI (Theory and Practice of Frozen Dough)", for instance, p. 17 (1982), Published by SHOKKEN SENTAR (Food Research Center)].
To eliminate these drawbacks, there have been known methods which comprise reducing the amount of water to be supplied to baker's dough; increasing the amount of yeast; using freeze-resistant yeast; increasing contents of saccharides such as sugar and fats and oils; and adding an oxidizing agent such as potassium bromate or ascorbic acid. There have also been proposed a variety of methods in addition to those described above.
There have been developed, for instance, a method which comprises adding non-reduced oligosaccharides such as tri- or higher saccharides and/or reduced oligosaccharides such as dior higher saccharide alcohols (Japanese Un-Examined Patent Publication (hereinafter referred to as "J. P. KOKAI") No. Hei 4-141041); a method comprising adding lactitol (J. P. KOKAI No. Hei 4-141042); a method comprising adding an indigestible polysaccharide and/or a yeast-nonassimilable sugar (J. P. KOKAI No. Hei 5-252858); a method comprising adding a mixture of gelatin with an emulsifier such as enzyme-decomposed lecithin or a monoglyceride (J. P. KOKAI No. Hei 4-234938); and a method comprising adding a hot water-soluble gelling agent (e.g., gelatin) which does not undergo gelation within the final fermentation temperature range of the baker's dough (J. P. KOKAI No. Hei 5-292872).
Moreover, the use of starch has also been proposed. For instance, J. P. KOKAI No. Hei 4-158731 discloses a method comprising adding a cold water-soluble starch and/or lipase. In this patent, the cold water-soluble starch should have a viscosity of not less than a predetermined level on the basis of such an idea that the deterioration of the baker's dough due to freezing can be eliminated by reducing the amount of the free water present therein and pregelatinized potato starch is disclosed as an example thereof. However, this method suffers from various problems such that the use of cold water-soluble starch having such a high viscosity leads to an increase in the stickiness of the resulting dough and this in turn makes the kneading and molding operations difficult and that, in particular, if a starch decomposition enzyme is simultaneously used, the pregelatinized potato starch is first decomposed and the shape retaining properties of the resulting dough is accordingly impaired.
On the other hand, there have been proposed bakery foods which have excellent taste and texture and improved maintenance of quality over a long time period and which can be prepared through the use of processed starch having specific hot water solubility, particle size, cold water swelling power and hot water swelling power (J. P. KOKAI No. Hei 5-15296) and also suggested that this technique may be applied to frozen dough. However, it has been found out, during the studies subsequent thereto, that the use of the processed starch alone is effective only when the resulting dough is stored in the frozen state for a short period of time on the order of not more than about one week, but the freeze resistance thereof is reduced as the freezing time increases.
As has been described above, there have been proposed various approaches and attempts in order to overcome the drawbacks which are encountered when frozen baker's dough is used for baking bread, but none of them have succeeded in the preparation of bread, starting from the baker's dough stored in the frozen state, which have quality comparable to that of the bread produced by the usual integrated work. More specifically, they permit the production of bread having a rich formulation whose quality is approximately identical to that of the bread produced by the integrated work, but have not yet permitted the production of any bread having a lean formulation which shows sufficiently satisfactory quality.